Using die cut adhesive tapes in auto manufacturing

Especially in the automotive sector, die cut tapes can improve efficiency, reduce re-work, save time, cut costs and enhancing quality.

Custom made pressure sensitive and non-pressure sensitive adhesive tape die cuts that provide solutions to manufacturing problems have developed rapidly in technology and application across many industries, but especially in the automotive sector.

Here they are employed for many tasks such as the positioning and mounting of wing mirrors, masking orifices on dashboards to prevent foam injection overflow, sealing holes on vehicle chassis and fixing badges.

In every case they improve efficiency, reduce re-work, save time, cut costs and enhancing quality.

Die cuts are simply shapes cut from a given material using a die.

However the route to specification involves consideration of many parameters and calls for much knowledge and experience says Bob Jary of Beiersdorf UK - tesa Division, Europe's No.1 adhesive tape manufacturer.

Typically, thought needs to be given to the material type to be used, adhesive system, tolerance required, volume and presentation.

Once feasibility has been established die cutting tooling and machinery can be selected to suit.

Generally there are four main tooling options: steel rule, two part die cut set, rotary die or rotary flexi die.

Cutting tolerances can be achieved down to ± 0.003mm subject to the material being cut.

Presentation is key Presentation of the individual die cuts is a key element of the process.

So called 'finger lift' tabs can be designed-in to facilitate ease of use relative to the product or manufacturing process to ensure cost effective application and minimise operator fatigue.

Line supply options can include roll form, dry edge, split liner, sprocket holed, pads, sheets or even a combination of these.

A die cut may comprise a pressure sensitive material laminated to a non- pressure sensitive material.

It may feature varying thicknesses, strip or zone lamination and use any number of adhesives such as acrylic, rubber based, synthetic, thermosetting, silicone, even hypoallergenic.

Successful die cuts have been made up with copper film, polyester, pe and pu foam, electrical insulating materials, water resistant cloth, glass cloth and neoprene rubber, but materials can include simple label stock, vinyl, cloth and film.

Any part of a die cut can be overprinted to give instructions on use or to identify products.

If necessary subsequent over-lamination can protect messages from local hazards such as solvents or abrasion.

Adhesive technology A major contributor to the growth in the use of die cuts is the advance in adhesive technology over the past decade.

Most performance requirements can be accommodated simply by specifying the right adhesive system.

In general terms good surface contact is fundamental to performance and this means that surfaces must be dry and free from contamination whilst the adhesive must reliably respond to the pressure employed to apply it.

Commonly used adhesives are: Rubber: for most general applications, features high tack and peel values, good for rough or curved surfaces Acrylic:for high shear applications, high temperature use and resistance to UV and plasticisers Silicone:for extremes of temperature where initial high tack is not required Cost savings A car dashboard serves as a good illustration of how die cuts can be applied and the cost savings that can accrue.

Consider a metal dashboard with foam insulation for sound deadening purposes where the foam is applied by injection through two holes in the front of the fascia.

During processing the foam overflows back outwards at these points whilst curing, subsequently condemning the part to the re-work bin.

A die cut is developed to cover the holes, which, on removal by means of a 'finger lift' tab, takes any residual foam with it.

If the die cuts cost 10p each, and two are used per dashboard with10,000 dashboards produced each month, the total cost of the die cuts is £2000 per month.

Without the die cuts there is a risk of 100% re-work, which means the foam has to be manually scraped from the dashboard, costing 40p per time - or £4000 per month.

The resultant saving is £2000 per month.

Over an 11 month production cycle this adds up to £22,000.

A laminated and perforated tab is also used on the dashboard as a surface protection tape.

When assembled with the windscreen the tab is torn along the perforation to leave a clean surface onto which the glass can be bonded.

All tesa self-adhesive materials can be cut to any size and shape, combined with other materials, printed or made into ready-to-use die- cuts.

As die-cuts are custom made and developed to provide solutions their successful use depends on the experience of application engineers.

Over the years Beiersdorf UK - tesa Division has built up a massive European industry-wide databank of knowledge on the subject and now aims to deliver the service direct through its tesanet Distributor network.

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